Hydroforming die assembly and method for deforming a tube

ABSTRACT

A hydroforming die assembly for deforming a tube and a method for deforming the tube are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/376,926, filed on Aug. 25, 2010, the entire contents of which arehereby incorporated by reference herein.

BACKGROUND

Hydroforming systems have been utilized to deform tubes. However, thehydroforming systems may at least partially crush pipes in the centralregions of the pipes. Accordingly, the inventors herein have recognizeda need for an improved hydro forming die assembly and method.

SUMMARY

A hydroforming die assembly for deforming a tube in accordance with anexemplary embodiment is provided. The hydroforming die assembly includesa lower die having a first cavity formed therein. The hydroforming dieassembly further includes a vertically movable upper die disposed abovethe lower die. The vertically movable upper die has a second cavityformed therein. The hydro forming die assembly further includes a firstsealing assembly disposed proximate to a first end of the lower die. Thefirst sealing assembly has a first subplate, a first feed insert, afirst axial cylinder, and a first seal cone. The first seal cone iscoupled to the first axial cylinder. The first feed insert and the firstaxial cylinder are coupled to the first subplate. The first subplate isconfigured to move vertically. The hydroforming die assembly furtherincludes a second sealing assembly disposed proximate to a second end ofthe lower die. The second sealing assembly has a second subplate, asecond feed insert, a second axial cylinder, and a second seal cone. Thesecond seal cone is coupled to the second axial cylinder. The secondfeed insert and the second axial cylinder are coupled to the secondsubplate. The second subplate is configured to move vertically. Thefirst and second feed inserts are configured to initially support thetube above the lower die. The upper die is configured to move verticallydownwardly to contact the tube when the tube is supported on the firstand second feed inserts. The first and second axial cylinders areconfigured to move the first and second seal cones, respectively, towardfirst and second ends of the tube, respectively, to seal the first andsecond ends of the tube, respectively. The first and second seal conesare configured to increase a pressure of a fluid disposed in the tube toobtain pressurized fluid therein. The upper die is further configured tomove further vertically downwardly against the tube while the tube hasthe pressurized fluid therein such that the first and second sealingassemblies are moved vertically downwardly and the tube is at leastpartially deformed into the first and second cavities.

A method for deforming a tube utilizing a hydroforming die assembly inaccordance with another exemplary embodiment is provided. Thehydroforming die assembly has a lower die with a first cavity formedtherein, a vertically movable upper die with a second cavity formedtherein, and first and second sealing assemblies. The first sealingassembly has a first subplate, a first feed insert, a first axialcylinder, and a first seal cone. The first feed insert and the firstaxial cylinder are coupled to the first subplate. The first subplate isconfigured to move vertically. The second sealing assembly has a secondsubplate, a second feed insert, a second axial cylinder, and a secondseal cone. The second feed insert and the second axial cylinder arecoupled to the second subplate. The second subplate is configured tomove vertically. The method includes supporting the tube above the lowerdie utilizing the first and second feed inserts. The method furtherincludes moving the upper die vertically downwardly to contact the tubewhen the tube is supported on the first and second feed inserts. Themethod further includes moving the first and second seal cones,respectively, toward first and second ends of the tube, respectively, toseal the first and second ends of the tube, respectively, utilizing thefirst and second axial cylinders, respectively. The method furtherincludes increasing a pressure of a fluid disposed in the tube to obtainpressurized fluid therein utilizing the first and second seal cones. Themethod further includes moving the upper die further verticallydownwardly against the tube while the tube has the pressurized fluidtherein such that the first and second sealing assemblies are movedvertically downwardly and the tube is at least partially deformed intothe first and second cavities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a hydroforming system in accordance with anexemplary embodiment;

FIG. 2 is an enlarged view of a portion of a hydroforming die assemblyutilized in the hydroforming system of FIG. 1; and

FIGS. 3-10 illustrate different operational positions of thehydroforming die assembly utilized in the hydroforming system of FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a hydroforming system 10 for deforming a shape of atube 12 utilizing fluid within the tube 12 in accordance with anexemplary embodiment is illustrated. The hydroforming system 10 includesa hydroforming die assembly 13, an actuator 14, a fluid supply system15, and a controller 16. The tube 12 is constructed of a metal. Forexample, the tube 12 can be constructed from at least one of steel,aluminum, copper, and stainless steel.

The hydroforming die assembly 13 is configured to deform the tube 12 toa desired shape utilizing pressurized fluid within the tube 12. In oneexemplary embodiment, the fluid is a water-based fluid. Of course, othertypes of fluids could be utilized. The hydroforming die assembly 13includes a lower baseplate 20, an upper baseplate 22, a lower die 24, anupper die 26, a sealing assembly 30, a sealing assembly 32, and anejector unit 33.

The lower baseplate 20 is configured to hold the lower die 24 and thesealing assembly 30 thereon. The lower baseplate 20 is constructed ofsteel and is substantially rectangular-shaped.

The upper baseplate 22 is configured to hold the upper die 26, and theupper feed inserts 52, 102 thereon. The upper baseplate 22 is operablycoupled to the actuator 14. The actuator 14 is configured to move theupper baseplate 22 vertically, either upwardly or downwardly, relativeto the lower baseplate 20 in response to control signal from thecontroller 16. The upper baseplate 22 is constructed of steel and issubstantially rectangular-shaped.

Referring to FIGS. 1 and 3, the lower die 24 has a first cavity 35formed therein for shaping at least a portion of the tube 12. The lowerdie 24 is constructed of a hardened steel and is fixedly coupled to thelower baseplate 20. In an alternative embodiment, the lower die 24 couldhave more than one cavity therein.

The upper die 26 has a second cavity 36 formed therein for shaping atleast a portion of the tube 12. The upper die 26 is constructed of ahardened steel and is fixedly coupled to the upper baseplate 22. In analternative embodiment, the upper die 26 could have more than one cavitytherein.

Referring to FIG. 1, the sealing assemblies 30, 32 are configured toseal first and second ends, respectively, of the tube 12 and to fill thetube 12 with a fluid and to increase a pressure of the fluid within thetube 12. Further, the sealing assemblies 30, 32 are configured to movevertically relative to the baseplate 20.

Referring to FIGS. 1 and 2, the sealing assembly 30 includes a subplate42, push bars 44, 46, a lower feed insert 50, an upper feed insert 52, aseal cone 60, and an axial cylinder 62. The subplate 42 is constructedof steel and is biased above the baseplate 20 utilizing springs 63, 64that are disposed between the subplate 42 and the baseplate 20. Thesprings can be at least one of metal springs, plastic springs, and gasloaded springs. In an alternative embodiment, the springs can bereplaced by a hydraulic cylinder operably coupled between the subplate42 and the baseplate 20.

The push bars 44, 46 are disposed on the subplate 42 on opposite sidesof an axial cylinder 62 disposed on the subplate 42. The push bars 44,46 are constructed of steel. When the upper baseplate 22 is loweredtowards the lower baseplate 20, the push bars 44, 46 contact a lowersurface of the baseplate 22 to urge the subplate 42 downwardly againstthe biasing force of the springs thereof.

The lower feed insert 50 is coupled on the subplate 42 proximate to afirst end of the tube 12. The upper feed insert 52 is coupled to theupper baseplate 22 directly above the lower feed insert 50. The lowerfeed insert 50 and the upper feed insert 52 are configured to clamparound an end portion of the tube 12 when the actuator 14 moves theupper baseplate 22 toward the lower baseplate 20.

The seal cone 60 is operably coupled to the axial cylinder 62. The axialcylinder 112 is configured to move the seal cone 60 axially, eithertoward the tube 12 or away from the tube 12, in response to controlsignals from the controller 16. When the axial cylinder 62 moves theseal cone 60 toward the tube 12, the seal cone 60 seals a first end ofthe tube 12. The seal cone 60 includes an aperture extendingtherethrough for allowing fluid to flow through the seal cone 60 into aninterior region of the tube 12. The seal cone 60 is fluidly coupled tothe fluid supply system 15 for receiving pressurized fluid from thesystem 15.

Referring to FIG. 1, the sealing assembly 32 includes a subplate 92,push bars 94, 96, a lower feed insert 100, an upper feed insert 102, aseal cone 110, and an axial cylinder 112. The subplate 92 is constructedof steel and is biased above the baseplate 20 utilizing springs 113, 114disposed between the subplate 92 and the baseplate 20. The springs canbe at least one of metal springs, plastic springs, and gas loadedsprings. In an alternative embodiment, the springs can be replaced by ahydraulic cylinder operably coupled between the subplate 92 and thebaseplate 20.

The push bars 94, 96 are disposed on the subplate 92 on opposite sidesof an axial cylinder 112 disposed on the subplate 92. The push bars 94,96 are constructed of steel. When the upper baseplate 22 is loweredtowards the lower baseplate 20, the push bars 94, 96 contact a lowersurface of the upper baseplate 22 to urge the subplate 92 downwardlyagainst the biasing force of the springs thereof.

The lower feed insert 100 is coupled on the subplate 92 proximate to asecond end of the tube 12. The upper feed insert 102 is coupled to theupper baseplate 22 directly above the lower feed insert 100. The lowerfeed insert 100 and the upper feed insert 102 are configured to clamparound an end portion of the tube 12 when the actuator 14 moves theupper baseplate 22 toward the lower baseplate 20.

The seal cone 110 is operably coupled to the axial cylinder 112. Theaxial cylinder 112 is configured to move the seal cone 110 axially,either toward the tube 12 or away from the tube 12, in response tocontrol signals from the controller 16. When the axial cylinder 112moves the seal cone 110 toward the tube 12, the seal cone 110 seals asecond end of the tube 12. The seal cone 110 includes an apertureextending therethrough for allowing fluid to flow through the seal cone110 into an interior region of the tube 12. The seal cone 110 is fluidlycoupled to the fluid supply system 15 for receiving pressurized fluidfrom the system 15.

The ejector unit 33 is coupled to the lower die 24 and is configured tohold the tube 12 above the lower die 24, along with the lower feedinserts 50, 100, before closing the upper die 26 against the lower die24.

The controller 16 is configured to generate control signals to controloperation of the axial cylinder 62, 112, and the actuator 14. In oneexemplary embodiment, the controller 16 is a computer. In anotherexemplary embodiment, the controller 16 is a programmable logic unit.

Referring to FIGS. 3-10, a method for deforming the tube 12 utilizingthe hydroforming system 10 in accordance with an exemplary embodimentwill now be explained.

Referring to FIG. 3, initially, the actuator 14 moves the upperbaseplate 22 to a full upward position such that a relatively large gapis present between the lower die 24 and the upper die 26, in response toa control signal from the controller 16.

Next, referring to FIG. 4, the tube 12 is placed on the feed insert 50,100 such that the feed inserts 50, 100 support the tube 12 above thelower die 24.

Next, referring to FIG. 5, the actuator 14 moves the baseplate 22 andthe upper die 26 vertically downwardly such that the upper die 26contacts the tube 12 when the tube 12 is supported on the feed inserts50, 100. In one exemplary embodiment, the upper die 26 applies at least50 tons of force against the tube 12. Of course, other amounts of forcecould be utilized based on the desired tube deformation and tubematerial type.

Next, referring to FIG. 6, the axial cylinders 62, 112 move the sealcones 60, 110 toward the first and second ends, respectively, of thetube 12 such that the seal cones 60, 110 seal the first and second ends,respectively, of the tube 12. Further, the seal cones 60, 110 routepressurized fluid from the fluid supply system 15 into an interiorregion of the tube 12 to fill the tube 12 with the pressurized fluid.

Next, referring to FIG. 7, the actuator 14 moves the upper die 26further vertically downwardly against the tube 12 while the tube 12 hasat least some pressurized fluid therein such that the sealing assemblies30, 32 are also moved vertically downwardly (by the upper die 26contacting the push bars) and the tube 12 is at least partially deformedinto the cavities 35, 36. In one exemplary embodiment, the upper die 26applies a force of at least 5,000 tons on the tube 12. Of course, otheramounts of force could be utilized based on the desired tube deformationand tube material type.

Next, referring to FIG. 8, optionally the axial cylinders 62, 112 movethe seal cones 60, 110 further inwardly into the tube 12. Further, theseal cones 60, 110 route pressurized fluid into the tube 12 to increasea pressure level of the pressurized fluid within the tube 12 to deformthe tube 12 into the cavities 35, 36. In one exemplary embodiment, theseal cones 60, 110 route pressurized fluid into the tube 12 having apressure greater than a yield point pressure level (i.e., Pi_(max)) ofthe tube 12 to deform the tube 12 into the cavities 35, 36. The yieldpoint pressure level may be in a range of 8,000-20,000 psi for example.Of course, other amounts of yield point pressure levels could beutilized based on the tube material type.

Next, referring to FIG. 9, optionally the axial cylinders 62, 112 maymaintain the pressurized fluid in the tube 12 for 1-2 seconds forexample. Of course, other amounts of time could be utilized based on thetube material type and a shape of the cavities.

Next, referring to FIG. 10, the axial cylinders 62, 112 move the sealcones 60, 110, respectively, out of the first and second ends,respectively, of the tube 12 and the pressurized fluid within thedeformed tube 12 exits the deformed tube 12.

In an alternative embodiment of the above method, the method stepsillustrated in FIGS. 8 and 9 can be removed. For example, in analternative method, after performing the method steps of FIGS. 3-7, thesystem 10 can immediately perform the method step shown in FIG. 10 andobtain a deformed tube having a desired shape.

An advantage of utilizing the hydroforming system 10 is that the system10 can deform tubes without crushing central regions of the tubes.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description.

We claim:
 1. A hydroforming die assembly for deforming a tube,comprising: a lower die having a first cavity formed therein; avertically movable upper die disposed above the lower die, thevertically movable upper die having a second cavity formed therein; afirst sealing assembly disposed proximate to a first end of the lowerdie, the first sealing assembly having a first subplate, a first feedinsert, a first axial cylinder, and a first seal cone, the first sealcone coupled to the first axial cylinder, the first feed insert and thefirst axial cylinder coupled to the first subplate, the first subplateconfigured to move vertically; a second sealing assembly disposedproximate to a second end of the lower die, the second sealing assemblyhaving a second subplate, a second feed insert, a second axial cylinder,and a second seal cone, the second seal cone coupled to the second axialcylinder, the second feed insert and the second axial cylinder coupledto the second subplate, the second subplate configured to movevertically; the first and second feed inserts configured to initiallysupport the tube above the lower die; the upper die being configured tomove vertically downwardly to contact the tube when the tube issupported on the first and second feed inserts; the first and secondaxial cylinders configured to move the first and second seal cones,respectively, toward first and second ends of the tube, respectively, toseal the first and second ends of the tube, respectively, the first andsecond seal cones configured to increase a pressure of a fluid disposedin the tube to obtain pressurized fluid therein; and the upper die beingfurther configured to move further vertically downwardly against thetube while the tube has the pressurized fluid therein such that thefirst and second sealing assemblies are moved vertically downwardly andthe tube is at least partially deformed into the first and secondcavities.
 2. The hydroforming die assembly of claim 1, furthercomprising: the first and second axial cylinders further configured tomove the first and second seal cones, respectively, further inwardlyinto the first and second ends of the tube, respectively, the first andsecond seal cones further configured to further increase the pressure ofthe fluid in the tube to deform the tube into the first and secondcavities.
 3. A method for deforming a tube utilizing a hydroforming dieassembly, the hydroforming die assembly having a lower die with a firstcavity formed therein, a vertically movable upper die with a secondcavity formed therein, and first and second sealing assemblies, thefirst sealing assembly having a first subplate, a first feed insert, afirst axial cylinder, and a first seal cone, the first feed insert andthe first axial cylinder coupled to the first subplate, the firstsubplate configured to move vertically, the second sealing assemblyhaving a second subplate, a second feed insert, a second axial cylinder,and a second seal cone, the second feed insert and the second axialcylinder coupled to the second subplate, the second subplate configuredto move vertically, the method comprising: supporting the tube above thelower die utilizing the first and second feed inserts; moving the upperdie being vertically downwardly to contact the tube when the tube issupported on the first and second feed inserts; moving the first andsecond seal cones, respectively, toward first and second ends of thetube, respectively, to seal the first and second ends of the tube,respectively, utilizing the first and second axial cylinders,respectively; increasing a pressure of a fluid disposed in the tube toobtain pressurized fluid therein utilizing the first and second sealcones; and moving the upper die further vertically downwardly againstthe tube while the tube has the pressurized fluid therein such that thefirst and second sealing assemblies are moved vertically downwardly andthe tube is at least partially deformed into the first and secondcavities.
 4. The method of claim 3, further comprising: moving the firstand second seal cones, respectively, further inwardly into the first andsecond ends of the tube, respectively, utilizing the first and secondaxial cylinders, respectively; and increasing the pressure of the fluidin the tube to deform the tube into the first and second cavitiesutilizing the first and second seal cones.